Healthy adult volunteers are assigned randomly to either a vaccine or placebo group. Injections are received either intramuscularly, intradermally, or by delivery under the skin of the volunteer's own white blood cells which have had dendritic cell reinfusion. Volunteers are vaccinated at 0, 1, 3, and 6 month time points. Volunteers are closely monitored for 1 hour after vaccination and keep a diary of symptoms for 1 week post-immunization. Volunteers undergo leukopheresis at the start of the study and after the last vaccination at Walter Reed Army Medical Center. Volunteers receive compensation benefits.